1. Field of the Invention
The invention relates to an electric connector to be used for electrical connection between devices equipped in an automobile or various industrial machines, and specifically, to an electric connector including a lock arm equipped in an electric connector to connect the electric connector to another electric connector.
2. Description of the Related Art
Japanese Patent Application Publication No. 2005-135751 discloses an electric connector including a lock arm, a releasing unit formed at a rear end of the lock arm, and a flexible support portion formed between the lock arm and an upper surface of a female housing to extend in a front-rear direction. In the electric connector, the lock arm is connected to the support portion at a location closer to a front end than a rear end of the support portion, ensuring that the lock arm and the support portion can be arranged in a small space above an upper surface of the female housing in comparison with an electric connector having a lock arm connected to a support portion at a location closer to a rear end than a front end of the support portion, and thus, the female connector can be down-sized.
Japanese Patent Application Publication No. 2013-30323 discloses an electric connector including a lock arm, an engagement hook to be engaged with an engagement hole formed at a connector housing when the electric connector is inserted into the connector housing, and a lock-releasing unit for releasing the engagement hook from the engagement hole when the lock arm is pushed towards a rear of the connector housing beyond the engagement hook, a fulcrum located closer to a rear end being positioned closer to the engagement hook than a fulcrum located closer to a front end in a direction opposite to a direction in which the engagement hook extends.
FIG. 13 illustrates an example of an inner housing of a conventional electric connector including a lock arm, and FIG. 14 illustrates an example of an outer housing into which the inner housing is inserted.
As illustrated in FIG. 13, a lock arm 51 is formed above an upper surface of an inner housing 50. As illustrated in FIG. 14, an outer housing 40 includes a hood 41 having a rectangular cross-section, into which the inner housing 50 is inserted. The hood 41 includes on an inner surface of an upper wall a recess 42 into which the lock arm 51 of the inner housing 50 is inserted. A plurality of metallic terminals 43 (see FIG. 16) extend in the hood 41 in a direction in which the inner housing 50 is inserted into the outer housing 40.
The lock arm 51 of the inner housing 50 includes a lock arm body 52, a front leg 53 supporting a front end of the lock arm body 52 on an upper surface of the inner housing 50, a rear leg 54 supporting a rear end of the lock arm body 52 on the upper surface of the inner housing 50, a lock projection 55 to be locked with a lock unit (not illustrated) located in the recess 42 formed at the hood 41 of the outer housing 40, and a releasing unit 56 for releasing the lock projection 55 from the lock unit.
As illustrated in FIG. 14, an electric connector including the hood 41 having a relatively great width of an opening is accompanied with a problem in that if the lock projection 55 has a relatively small width, the inner housing 50 is readily inclined relative to the outer housing 40 when cables connected to metallic terminals inserted into the inner housing 50 are pulled. Thus, the lock projection 55 may be designed to have a relatively great width in order to avoid the problem.
As illustrated in FIG. 15, the lock projection 55 designed to have a width WB greater than an initial width WA outwardly transfers a point at which the inner housing 50 starts inclining with the result that the inclination of the inner housing 50 is made smaller. However, the lock projection 55 having the greater width WB causes a problem in that if the inner housing 50 is inserted in an inclined condition into the outer housing 40, as illustrated in FIG. 16, the inner housing 50 may be inserted deeply into the outer housing 40, resulting in that the inner housing 50 makes contact with the metallic terminals 43 extending in the inner housing 40 to thereby cause the metallic terminals 43 to be bent and/or damaged.